Relative Fat Mass Associated with Hyperuricemia in Adults: A Cross-Sectional Study

There is a close relationship between obesity and hyperuricemia. Relative Fat Mass (RFM) is considered a new indicator for evaluating obesity. We aim to explore the relationship between RFM and the risk of hyperuricemia in adults.

This cross-sectional study included adult participants from the 2007-2018 National Health and Nutrition Examination Survey (NHANES). The RFM was calculated as: RFM =64 - (20 × height/waist circumference) + (12 × sex), where sex is defined as 0 for men and 1 for women. Hyperuricemia was confirmed by using serum uric acid (SUA) levels ≥ 7 mg/dL in men and ≥ 6 mg/dL in women. The relationship between RFM and the risk of hyperuricemia was thoroughly investigated.

A total of 29369 participants were enrolled in this study. The RFM levels in the hyperuricemia group were higher than those in the non-hyperuricemia group (P < 0.01). Logistic and linear regression indicated that RFM levels were positively associated with the risk of hyperuricemia (OR=1.08, 95% CI: 1.05-1.11, P < 0.001) and SUA levels (β=0.04, 95% CI: 0.03-0.05, P < 0.001). The relationship remained consistent across subgroups. Smooth curve fitting showed a nonlinear relationship, with an inflection point at 34.22. Above this threshold, the link between RFM levels and hyperuricemia was found to be more remarkable.

Higher RFM is associated with an increased risk of hyperuricemia. RFM could act as a cost-efficient and straightforward measure for hyperuricemia risk assessment.